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Around here I have witnessed the decline in direct steam and hydronic heat in new construction, new commercial buildings use water source heat pumps with primary secondary loops.
High pressure steam boilers have stationary engineers on duty 24/7, low pressure boilers in most cases do not.
Steam is slowly fading away in the comfort heating market but it has its place for the years to come in the industrial sector.

Another question I have; " Are high pressure boilers used only in older properties"?? It seems that this method of heating hasn't been used in new construction for 30+ years. Are there any newer buildings that utilize this type of heating??

Johnson Controls did an Amazing renovation in Childrens Hospital serving Philadelphia, Pennsylvania. The safety valve testing once a year is important; however, when new controls are added onto vessels rated for capacity there is a tendency to run into a breaching that sheds tears to the fire tubes causing the unit to crack... What your hinting at is correct, system replacement is better than overcontrolled. For example, there was a building I recall working on that used a glycol loop from five tandom boilers all 100k btu. Another building used some 300k pork chops with cast iron exchangers, and yet another building had three cleaver brookes fire tubes, a fuel cell 250kw, and three 20 ton trane air handlers, and trox units for perimeter zoning. The important thing to remember is control control control.

I've even seen some guys in commercial applications put ball valves on top of expansion tanks.. Older properties are expensive to convert to the newer technologies which save the facility dollars. The tandom boilers were small household low pressure boilers; yet, served the building in a manner that was far more green than the supplemented cleaver brookes with a 250kw fuel cell that prob. never sold any power back to the grid.

Around here I have witnessed the decline in direct steam and hydronic heat in new construction, new commercial buildings use water source heat pumps with primary secondary loops.
High pressure steam boilers have stationary engineers on duty 24/7, low pressure boilers in most cases do not.
Steam is slowly fading away in the comfort heating market but it has its place for the years to come in the industrial sector.

Yes, I would agree that nearly all new buildings utilize heat pumps or RTUs with electric or gas heat. From what I can tell Steam isn't fading away, it has faded away completley for newly constructed buildings.

Others have tried to state otherwise, yet I would say the transition was around 1981/1982. Any building, built about 1981 or earlier seems to utilize steam or hot water heat provided by on site boilers or district steam. Newer buildings constructed from about 1982 to the present appear to utilize electric heat strips or heat pumps.

Hydronic is no longer installed unless it is being repaired or replaced in the renovation of a OLD building. Someone in another forum stated that no one wants to install boilers in newly built buildings because of the initall cost. However, I wonder why newly built buildings do not want to utilize the district Steam loop when avilaible??? This is an unanswered question for me.

This makes me wonder when the transition from chilled water to DX units and RTUs occured. If I had to quess I would say it was around the same time.

Yes, I would agree that nearly all new buildings utilize heat pumps or RTUs with electric or gas heat. From what I can tell Steam isn't fading away, it has faded away completley for newly constructed buildings.

Steam is alive and well in many areas of the country... Our boiler vendors sell a whole bunch of smallish steam boilers for new construction, there has been an incredible surge in condensing boilers as well. Your statement may hold some truth in your neck of the woods, but rings completely false here.

Originally Posted by MHall

Others have tried to state otherwise, yet I would say the transition was around 1981/1982. Any building, built about 1981 or earlier seems to utilize steam or hot water heat provided by on site boilers or district steam. Newer buildings constructed from about 1982 to the present appear to utilize electric heat strips or heat pumps.

Disagree... This would be very irresponsible here and you have a difficult time get it permitted, we have Title 24 restrictions that restrict the use of electric heat strips. Basically states emergency only.

Originally Posted by MHall

Hydronic is no longer installed unless it is being repaired or replaced in the renovation of a OLD building. Someone in another forum stated that no one wants to install boilers in newly built buildings because of the initall cost. However, I wonder why newly built buildings do not want to utilize the district Steam loop when avilaible??? This is an unanswered question for me.

Hydronic heat is no more costly when efficiency and serviceability is taken into account, we are doing 4 huge buildings in our area right now that all have boilers with reheat, one of them is a LEED building and uses heated floors.

Originally Posted by MHall

This makes me wonder when the transition from chilled water to DX units and RTUs occured. If I had to quess I would say it was around the same time.

Chillers are actually gaining in popularity. Large DX systems are out there, but a chiller for a large building cannot be beat, I don't care how long you argue that one.

Originally Posted by MHall

Thanks again for the insight.

You don't seem to be listening to it.

GT

If a day goes by and you have learned nothing, I hope you got a lot of sleep.

The NY Times building uses steam and hot water. It started construction in 2003. Check out 1 Bryant Park (Bank of America Tower). they're LEED Platinum certified and have some chilled water/heating plant...

Where have you seen that new new buildings don't want to utilize city/district steam? I don't get it either... but around here, I don't think that's much of an issue.

BTW, I'm definitely not trying to argue with you. Just showing that some things that you say are not happening, still are.

The NY Times building uses steam and hot water. It started construction in 2003. Check out 1 Bryant Park (Bank of America Tower). they're LEED Platinum certified and have some chilled water/heating plant...

Where have you seen that new new buildings don't want to utilize city/district steam? I don't get it either... but around here, I don't think that's much of an issue.

BTW, I'm definitely not trying to argue with you. Just showing that some things that you say are not happening, still are.

Thanks again for the info. There is no argument here, so don’t worry about that. I'm simply curious about the various changes in equipment installed throughout the years. It appears that we have heard different sources of information.

As I stated earlier, I was an apprentice at an office tower this past summer before school started. One of the engineers I worked with stated that he was previously employed at another building which was only a few years old. When I asked about the HVAC equipment he stated that the building was; "moving away from chillers". Apparently all 20+ floors had DX units and DDC controls. According to this crew DDC controls are ALWAYS installed in new construction, rather than pneumatics. Of course that’s another subject, which could be analyzed as well...

Regarding the discussion about boilers; this engineer as well as the other three in our crew gave the impression that nearly every building they had worked in had electric strip heat. When I asked about boilers they were unfamiliar with hydronic heat for the most part. One of the guys said he had worked in a complex of office towers fed by a boiler plant. However the complex was built way back in the 1950s, and was not in the greatest condition. This is one source for my understanding that this type of heating was now considered antiquated and had been abandoned in favor of other heat sources such as electric.

I had this discussion with someone else, and they stated that the reason boilers are no longer used in newly built buildings is because the contractors/building owners don’t want to pay for the additional supply and return piping which can be avoided by having electric heating elements in the ductwork.

I find it fascinating to learn about the various trends in building design, and the impact HVAC has on it.

QUOTE GT JETS "Disagree... This would be very irresponsible here and you have a difficult time get it permitted, we have Title 24 restrictions that restrict the use of electric heat strips. Basically states emergency only."

Are you refering to electric heat strips in the ductwork or air handlers?? As I mentioned the 15+ story building I worked in was heated entirely by heatrix boxes and electric baseboard. I never heard of any restrictions for electric heat.

QUOTE GT JETS "Disagree... This would be very irresponsible here and you have a difficult time get it permitted, we have Title 24 restrictions that restrict the use of electric heat strips. Basically states emergency only."

Are you refering to electric heat strips in the ductwork or air handlers?? As I mentioned the 15+ story building I worked in was heated entirely by heatrix boxes and electric baseboard. I never heard of any restrictions for electric heat.

I have however heard of strict licensing regulations for boilers.....

I was referring to new construction utilizing ANY strip heat, baseboard, duct, unitary. I believe the only way you can get it passed for a permit here is if it is supplementary/emergency heat in a heat pump or powered by a green source like solar or wind generation.

A boiler on the other hand has few restrictions other than the obvious and also needs to be low NOX.

We can actually get utility paybacks if we can rid an existing building of excessive electrical loads such as electric heat, many times paying for up to 10% of the job. You can't ignore that.

GT

If a day goes by and you have learned nothing, I hope you got a lot of sleep.

I personally feel that the largest advancements in mechanical systems in buildings is what we are allowing to leave the tail pipe (so to speak).

With the new refrigerants (personally whole heartedly disagree with R410A "Puron") and low NOX technologies we are starting to see some of the cleanest buildings in the world.

I had the opportunity to service a zero carbon emission building in Silicon Valley. Cutting edge stuff.

Keep asking questions and you may just stumble on a better way do do things...

Just keep on mind that most people that can think outside the box learned to think inside it first...

Speaking of emmisons that may be one reason for the movement away from boilers....? Perhaps the logic of the developers of a new building, is that electric heat is more environmentaly friendly because there is no flue?

The information that they Engineers had told you may be how things are trending in your neck of the woods.

DDC is almost always installed in new construction. The building I work in now was built 2003. It's all pneumatics... but yes pneumatics are no longer what they used to be. McQuay has the contract for 1 world trade, all smaller dx units. No more chillers like the originals. But there's going to be a 10,000 ton or so plant for the museum and memorial. So yeah, nothing is dead...

If you ask some engineers that work in Hospitals or Colleges in your area, you're probably going to get a completely different answer than what the guys in the office buildings had told you.